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Compact 4-pin trailer light tester with LED indicators, 6.5 by 3.74 by .7 inches

True MODS 8542039913 4-Way Flat Trailer Light Tester electrical system tool

SKU CH-5M89-4Z43E MPN 8542039913

Tests 4-pin trailer lighting circuits with LED indicators, plugging inline between vehicle and trailer to isolate wiring faults without tools

  • Team affiliation1 Piece
  • Key featuresCorded Electric, false
  • Overall height6.5 L x 3.74 W x 0.7 H inches
  • Overall width6.5 L x 3.74 W x 0.7 H inches
  • Overall length6.5 L x 3.74 W x 0.7 H inches
  • Product typeElectrical Measurement Device
  • Quickly test trailer lights by plugging inline and reading LEDs
  • Isolate wiring faults to tow vehicle or trailer side instantly
  • No tools required with plug-and-play 4-pin connection
  • Weather, corrosion and impact resistant construction lasts years
  • Compact 6.5 x 3.74 x .7 inch design stores in glove box

True MODS 4-Way Flat Trailer Light Tester

This tester plugs inline between a tow vehicle and a trailer to verify 4-pin wiring circuits. LED indicators show power and ground continuity for each lighting function. The plug-and-play design requires no additional tools for operation. It suits anyone who tows trailers with standard flat connectors.

Replaces manual probing of trailer sockets

Instead of using a multimeter or test light on each pin, this device splits the harness in half to isolate faults to the vehicle side or trailer side. The jump is worth it when you want a faster way to locate wiring breaks without crawling under the vehicle with loose probes. It eliminates guesswork during roadside or pre-trip checks.

Fits standard 4-pin flat connectors on both

The compact housing measures 6.5 L x 3.74 W x .7 H inches, so it stores easily in a glove box or door pocket. It needs only the existing trailer plug and vehicle socket to function. The two-sided design lets you leave it installed during a trip or remove it quickly when testing is done.

How it compares

Measured against everything we stock in Multimeters & Electrical Testers, at today’s prices. Recalculated every night.

Price $18.99
Cheaper than about 83% of the 971 comparable items (median $30.99).

Specifications

Product
Brand nameONLINE LED STORE
Product typeElectrical Measurement Device
Size & build
Overall height6.5 L x 3.74 W x 0.7 H inches
Overall width6.5 L x 3.74 W x 0.7 H inches
Overall length6.5 L x 3.74 W x 0.7 H inches
More details
Team affiliation1 Piece

Questions about this item

What size 4-pin flat connector does the tester accept?

It plugs directly into a standard 4-pin flat trailer adapter, both male and female ends, with no adapters required.

How do I install the tester to check the circuit?

Plug it inline between the tow vehicle and trailer, turn on the lights, then read the LEDs; the step often missed is testing the vehicle side first before the trailer side.

Will the LED indicators or housing need replacement over time?

The weather, corrosion and impact resistant housing is built for years of service with no user-serviceable parts inside.

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